The present invention relates to a method and apparatus for counting and delivering a plurality of paste-applied and folded cardboard sheets delivered by a paste-applying and folding machine of a cardboard box manufacturing apparatus, in the form of a plurality of successive batches each consisting of a prescribed number of said sheets, to a binding machine that is adapted to bind the cardboard sheets.
Typically, cardboard sheets are initially subjected to a paste applying and folding step before being counted and stacked into a batch having a prescribed number of sheets. The device employed as part of the counting and stacking operation is referred to herein as a counter ejector. Examples of known counter ejectors are the free drop type device as shown in FIG. 1 and an under-feed type device as shown in FIGS. 2 and 3.
Referring first to the free drop type counter ejector and delivering device shown in FIG. 1, a plurality of cardboard sheets 4 are delivered by conveyor rolls 1, 2 and 3 which constitute the delivery section of a paste-applying and folding machine of the preceding step. The sheets are then dropped and accumulated in a first hopper 5 where the sheets are squared by continuous reciprocating motion of squaring plate 6. Among the sheets 4 accumulated in the first hopper 5, the lowermost sheet 4 is conveyed by a suction conveyor 7 passing the lower end of the back stop 8 to a second hopper 9.
The sheets being delivered to hopper 9 are counted and arranged in a prescribed number of sheets for delivery to a binding step. For this purpose a photoelectric tube 10 counts the sheets 4 delivered to second hopper 9, and movable table 12 cooperates with side ledge 13 to divide the stacked sheets into the prescribed number for further processing. Specifically, sheets 4 carried by the suction conveyor 7 are counted one by one by a photoelectric tube 10 disposed at the inlet portion of the second hopper 9. As sheets 10 are delivered into second hopper 9 they are projected to strike front abutment 11 and are successively stacked on a table 12 which is movable up and down.
As the photoelectric tube counts a prescribed number of sheets, a side ledge 13 is projected to carry subsequent delivered sheets above the prescribed number. The batch consisting of a prescribed number of sheets stacked on the table 12 is then pushed forward toward a delivery conveyor 17 by means of a pusher 16 attached to a pair of chains 14 and 15. At this stage, the lower portion of the front abutment 11 is swung about a hinge 18 so as not to hinder the forward movement of the sheets 4.
Thus, in the free drop type device, the sheets are divided into batches while they are in the second hopper 9, so that the stacking and delivery of the sheets are conducted smoothly. In addition, since the sheets are counted one by one when they are discharged from the first hopper 5, the undesirable miscounting during stacking in the second hopper 9 is fairly avoided. On the other hand, however, this type of device poses various problems. For instance, since the arrangement is such that the sheets stacked in the first hopper are once released for counting and then divided into batches while they are in the second hopper, the length of the apparatus as a whole being inevitably long requires a large installation space and incurs a rise of the cost. In addition, since each sheet is set free when travelling between the first and the second hoppers, the sheet, which has been applied with paste and folded in the preceding step before the drying of the paste, exhibits a repulsive force to unfold while it is on the suction conveyor 7. As a result, the sheet cannot be delivered to the second hopper smoothly and may cause troubles such as jamming.
In the underfeed apparatus successive sheets are delivered beneath the accumulating stack rather than above the stack as in the free drop apparatus described above. As a result the batches formed are removed from the top of the stack for further processing. For facilitating the delivery of sheets and removal of the formed batches, a mechanism is provided which tends to move the accumulating sheets in an upward direction.
Referring now to the under-feed type device shown in FIGS. 2 and 3, the sheets 4 which have been applied with the paste and folded in the preceding step are delivered by conveyor 22 to conveyor 19 above which the sheets 4 are accumulated. A guide conveyor 20 is positioned relative conveyor 19 to engage a leading end of sheets 4 and force them upwardly. Conveyor 19 carries sheets 4 delivered to it in such a manner as to be pressed against a guide conveyor 20. At both sides of the outlet of the paste applying and folding machine, screws 21 and 21' are set in accordance with the width of the sheet. The folded sheet 4 is then received at its both sides by grooves of the screws 21 and 21' which are rotated in the direction to lift the sheet 4 received by their grooves. In consequence, the trailing end of the sheet 4 is gradually raised to facilitate the insertion of the leading end of the next sheet 4 thereunder. The guide conveyor 20 is driven in the upward vertical direction shown by the arrow in FIG. 3 at a low speed to facilitate entry of sheet 4 which is coming under the preceding sheet and to facilitate the lifting of the trailing end of the underlying sheet by the screws 21 and 21'. The sheets thus raised gradually are squared by a reciprocating movement of a squaring plate 23 and are further lifted gradually.
Disposed above these sheets thus lifted are chains 24 and 25 which have pushers 26 adapted to push the upper part of the pile of the sheets 4 toward delivery conveyor 27. The number of the sheets constituting the upper portion of the pile pushed by the pushers is determined by factors such as the ratio between the speed of operation of the paste applying and folding machine and the speed of chains. This ratio is usually changeable in about four stages.
As has been explained, this device has a simplified construction and requires only a small installation space. However, this construction suffers from a disadvantage in counting because the number of sheets constituting the batch forwarded by the pushers is determined by the height of the pile of the sheets the counting is made in an inaccurate manner. In addition, the surface of the sheets on which printing has been made in the preceding step may be stained during the forcible lifting of the sheets by the screws.